By Elvira Pollina MILAN (Reuters) -Italian state lender CDP and its partners have asked for more time to clinch a deal to buy Telecom Italia’s (TIM) network assets, TIM said on Monday, further delaying a project to create a unified broadband champion. CDP’s multi-billion bid is part of a long-held plan to combine TIM’s fixed network assets with those of state-backed rival Open Fiber to create a single national network operator under CDP control. The potential network sale is also a key plank of the strategy set out by TIM Chief Executive Pietro Labriola to turn around the debt-laden former pho…